Ceramide Levels Are Inversely Associated With Malignant Progression of Human Glial Tumors LAURA RIBONI, 1 * ROLANDO CAMPANELLA, 2 ROSARIA BASSI, 1 ROBERTO VILLANI, 2 SERGIO M. GAINI, 3 FILIPPO MARTINELLI-BONESCHI, 4 PAOLA VIANI, 1 AND GUIDO TETTAMANTI 1 1 Department of Medical Chemistry and Biochemistry, Study Center for the Functional Biochemistry of Brain Lipids, University of Milan, LITA-Segrate, Segrate, Milan, Italy 2 Department of Neurological Sciences, Neurosurgical Operative Unit, University of Milan, IRCCS Ospedale Maggiore Policlinico, Milan, Italy 3 Neurosurgical Clinic, Department of Neurosciences and Biomedical Technologies, University of Milan-Bicocca, S. Gerardo Hospital, Monza, Milan, Italy 4 Department of Neuroscience, Scientific Institute and University, Ospedale San Raffaele, Milan, Italy KEY WORDS sphingoid mediators; human astrocytomas; malignant progression ABSTRACT Ceramide represents an important sphingoid mediator involved in the signaling pathways that control cell proliferation, differentiation, and death. To determine whether ceramide levels correlate with the malignant progression of human astrocytomas, we investigated these levels in surgical specimens of glial tumors of low-grade and high- grade malignancy. Tumor samples obtained from 52 patients who underwent therapeutic removal of primary brain tumors were used. The tumors were classified according to standard morphologic criteria and were grouped into tumors of low-grade and high-grade malignancy. Sections of normal brain tissue adjacent to the tumor were also analyzed in 11 of the 52 patients. After extraction and partial purification, ceramide was measured by quantitative derivatization to ceramide-1-phosphate using diacylglycerol kinase and [- 32 P]ATP. Ceramide levels were significantly lower in the combined high-grade tumors compared with low-grade tumors and in both tumor groups compared with peritumoral tissue. The results indicate an inverse correlation between the amount of ceramide and tumor malignancy as assessed by both the histological grading and ganglioside pattern. Moreover, overall survival analysis of 38 patients indicates that ceramide levels are signif- icantly associated with patient survival. The present findings indicate that ceramide is inversely associated with malignant progression of human astrocytomas and poor prognosis. The downregulation of ceramide levels in human astrocytomas emerges as a novel alter- ation that may contribute to glial neoplastic transformation. The low ceramide levels in high-grade tumors may provide an advantage for their rapid growth and apoptotic resistant features. This study appears to support the rationale for the potential benefits of a ceramide- based chemotherapy. GLIA 39:105–113, 2002. © 2002 Wiley-Liss, Inc. INTRODUCTION Astrocytomas represent the most frequent and deadly primary intracranial neoplasias in humans and may be characterized by rapid growth, extensive hy- pervascularity, and invasiveness. The histopathologi- cal and clinical features of these tumors indicate that they can occur in different stages of malignancy, rang- ing from low-grade to high-grade tumors (Kleihues et al., 1993). Although some late-stage tumors appear to arise de novo, follow-up studies of patients with low- stage or medium-stage disease have shown that most will progress over time to a higher stage, supporting Grant sponsor: Italian Ministry of University and Scientific and Technological Research PRIN 2000; Grant sponsor: FIRST. *Correspondence to: Laura Riboni, Department of Medical Chemistry and Biochemistry, University of Milan, via Fratelli Cervi 93, LITA-Segrate, 20090 Segrate, Milan, Italy. E-mail: laura.riboni@unimi.it Received 18 December 2001; Accepted 22 March 2002 DOI 10.1002/glia.10087 Published online 00 Month 2002 in Wiley InterScience (www.interscience. wiley.com). GLIA 39:105–113 (2002) © 2002 Wiley-Liss, Inc.